Both would work. I explained their meanings in another question, but I'll paste here too.

The verb a trăi actually means to live, to be alive. So saying eu trăiesc may mean that I am alive. In this sense it can be used as an euphemism to say that someone is dead: el nu mai trăiește literally translated as he's no longer alive.

It can also be used to say eu trăiesc în Canada meaning that I live in Canada.

It can also be used to say something like eu trăiesc bine meaning that I live well. Former president of Romania, Traian Băsescu, once ended a speech with Să trăiți bine!

The verb a locui actually means to reside somewhere, to live there. So eu locuiesc în Canada also means that I live in Canada.

Both verbs can be used to say that we live together, yet noi locuim împreuna tends to have a physical sense (like roommates: Andrei și Mihai au locuit împreuna în timpul facultății), and noi trăim împreuna can mean more than that (like being significant others: Maria și Ion trăiesc împreună de cinci ani).